Generally, a flash memory is composed of a plurality of physical blocks and an upper limit is set to the number of erasures (the number of writes) of each physical block. A flash memory device including a flash memory performs memory lifetime control (leveling of the number of erasures) which is called wear leveling.
Storage apparatuses including a flash memory device and a storage controller that is a higher-level apparatus of the flash memory device are known. For example, in PTL 1, a storage controller notifies a flash memory device of an update frequency level and the flash memory device performs wear leveling based on the update frequency level from the storage controller. Update frequency levels include “hot” which is a level signifying that update frequency is comparatively high and “cold” which is a level signifying that update frequency is comparatively low. For example, hot data (data with high update frequency) is aggregated in one physical block. An update frequency level is determined by the storage controller based on an update frequency or based on whether or not data is parity data.